1. Technical Field
This invention relates to plumbing devices for preventing the flow of water in pipes, and more particularly, to a test plug device for sealing drainpipes.
2. Related Art
Devices for plugging pipes into prevent the flow of water are commonly used when testing pipe systems for leaks in homes, apartments or other buildings. When testing for leaks, the main drainpipe in a building is typically sealed or plugged via a side opening or clean-out pipe attached to the main drainpipe at a point near the main sewer line that serves the building. The building's pipe system is then typically pressurized by filling the system with water. The pressurized system is then inspected for leaks. Following completion of leak inspections, the device used to seal or plug the drain is removed to drain the water from the pipe system.
One type of plug device used to seal drainpipes is an inflatable cylindrical plug that is inserted into a drainpipe, and then pressurized with either air or water to block the flow of water within the drainpipe by expanding to completely seal the pipe. However, the pressure in a piping system filled with water increases in direct proportion to the height of the piping system. Consequently, devices used to seal main drainpipes in buildings must withstand an increasing amount of pressure as the height of the building increases. Inflatable cylindrical plugs are limited as to the external pressure they may withstand. As the pressure in a drainpipe begins to exceed the pressure within the inflatable plug, the plug will tend to compress, thereby allowing water to flow within the drainpipe. Increasing the pressure in the inflatable plug to compensate for increased pressure within the pipe increases the risk of rupture of the inflatable plug. Further, such devices tend to bleed pressure over time, thereby again allowing water to flow within the drainpipe. Consequently, the utility of such devices tends to be limited by the height of the piping system in which they are used, the pressure within that system, and the length of time that the device is pressurized.
Other devices have been developed that involve the use of solid plugs to seal or plug a drainpipe. Various mechanisms have been used to position such plugs within a drainpipe, and to hold the plugs in place when they are exposed to pressure in the drainpipe. For example, one device uses an elliptical plug coupled to an arm that is bolted to a cap, which in turn is coupled to the open end of a straight pipe. However, because this device is designed for use with a straight pipe it is not useful for plugging a pipe via a side opening or clean-out pipe attached to the main drainpipe.
Another device uses a solid plug that is inserted into a T, or 90-degree opening in the side of a pipe. A locking lever arm coupled to the plug is used to position the plug within the drain, and to lock the plug into position during use. However, as with the previously mentioned solid plug device, this device is not useful for plugging a pipe via a drain clean-out where the clean-out is at an angle other than approximately 90 degrees to the main drainpipe.
Therefore, in order to overcome the limitations of current pipe plug devices, what is needed is a plug device that is capable of withstanding increased pressure within a drainpipe for any desired length of time. Further, such a plug device should have the capability of being easily inserted through a drain clean-out or any other side opening to plug the drainpipe. Finally, such a plug device should be simple, capable of being easily fabricated and used, and should be inexpensive and durable.